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instead of entirely adjusting by tap flow, the water level is finally
raised by the displacement due to the wood block FJ. at (3), which
rests on a fulcrum L and is adjusted by screw M. The fluid heads
used in this experiment are very small, arid unless they can be
read to thousandths of an inch the results are of little value. A
telescope (7) is therefore bracketed near the scale R, both original
notch level and rise or head due to various discharges being
noted by its help. Lastly the float v at (5), carefully calibrated,
is placed vertically in tank B. It rises on guide wires w w, and
its wood scale of Ibs. of water is read on a fixed pointer z, all
carried on a base Y and upright a.
In an actual experiment under five different heads, viz. '84,
i'o8, 1*326, i '6, and 2-123 ins., the following data and results
were stated and obtained : —
1. Dimensions of notch.
2. Duration of each test (about 6 mins.)
3. Mean head at each test.
4. Total actual discharge.
5. Actual discharge per minute.
6. Theoretical discharge per minute.
7. Coefficient of discharge (^^tai)' .
8. Temperature of water.
The head was taken every quarter minute, and the mean
obtained therefrom for each separate test The lower tank being
too small for the whole discharge, the total actual discharge was
found by adding the separate fillings; and the discharge per
minute deduced from the time of test From p. 714: —
Theoretical discharge = f BHx
(or putting B and Hin inches) = 40*15 b1$ Ibs. per m.
Tabulating the results of the five tests :-